4 ZOOLOGICAL SKETCHES. 



cause. Like mange and prurigo, it is probably caused 

 by microscopic parasites. 



Dogs can be employed only where the game is very 

 abundant, for, if a band of cimarrons has been chased 

 twice or thrice in the same sierra, they are apt to leave 

 their old haunts forever or become so shy that the pur- 

 suit ceases to pay. A herd that has once smelt powder 

 is very hard to get at : their natural timidity becomes a 

 restless distrust, constant practice develops an almost 

 preternatural acuteness of their organs of sight and 

 smell, and they learn to recognize the form of their 

 arch-foe at a great distance and in all possible postures, 

 standing, crawling, or on horseback. If they can 

 only scent his approach without seeing him or knowing 

 his approximate whereabouts, they instantly decamp to 

 the windward, well knowing that thereby they will 

 either elude their enemy or ascertain his .position, pre- 

 ferring to bring matters to a crisis some way or another 

 rather than endure the torture of uncertainty. Among 

 the rocks of a high mountain-region the echo of remote 

 sounds is strangely deceptive ; the reverberations seem 

 to come from all sides at once, and on hearing a shot 

 or the boom of a distant rock-blast a whole herd will 

 often resolve itself into a committee of investigation, 

 scattering left and right, scrambling up the cliffs and 

 spying in every direction, then, returning, confer with 

 anxious looks and stamping hoofs, and disperse again 

 till they can agree upon the safest line of retreat. They 



